Volatility and risk: when not to enter

A high margin often hides high risk. How to read volatility, persistence, competition, churn and refill, tell a live trade from an illiquidity trap, and keep an exit rule. With a worked comparison of two items at the same margin but different risk.

Does a high margin always mean profit?

A big margin guarantees nothing on its own: most often it’s thin, illiquid stock with few trades. You buy in and then can’t sell for weeks — capital frozen. Profit comes from turnover, not from the spread number: 5% × 50 trades a day beats 60% × one trade a month.

The mechanism is simple: a wide spread lives where there are few trades, because no one steps in to narrow it. So a “fat” margin and illiquidity almost always travel together. The key metric against this trap is days of inventory: how many days the current depth lasts at the current turnover. A small days-of-inventory with a big margin almost always means a trap.

Which risk metrics should you check before entering?

Volatility — the daily price spread (σ): the higher, the riskier the entry, because the price can move against you while your order sits. Persistence — the share of time the spread stays wide: is the gap real or a one-off spike. Days of inventory — how long the current market depth lasts.

And turnover in ISK/day as a liquidity measure: it answers the key question — will you be able to get out. All four metrics live both in the Market columns (the “All” density) and in the “Signals” panel on the card. The value colour tells you at a glance whether the item is calm.

Competition, churn and refill

Margin is set not only by the spread but by how many others are like you. “Competition” is the number of orders in a narrow band near the best price on each side (buy/sell): the more there are, the more often you’ll have to re-price. “Churn” is how often the best order changes per hour: high churn means an aggressive fight for the top spot.

“Refill” is how many minutes the book takes to restock after it’s eaten. Fast refill is good for liquidity, but it also means both demand and supply are brisk — you won’t get to relax. The combo “high competition + high churn” often eats the very margin you came for.

The illiquidity trap

SKINs, blueprints and rare modules often show a giant “spread” off one or two trades. That’s a trap: there’s no volume and no way out. In Arbitrage the app filters such destinations out by daily volume at the sell hub — but on the raw Market screen the call is yours.

How do you know when to exit a position?

Risk management comes down to one thing: knowing how to exit in time. Before entering, set a threshold: if the line doesn’t fill within N days or the price moves X% against you — sell into the market, even at a loss. ISK frozen in illiquid stock costs more than one small realised loss: it isn’t working.

Example: same margin, two risks

Two items, both around a 40% margin. The first: steady turnover, 30+ trades a day, low volatility, a spread that holds for weeks, thick depth. The second: three trades in a week, the price jumping ±25%, the spread flipping between 40% and 5%, a single order on each side of the book. The margin is identical — yet these are two different universes. The first you can take and exit calmly; the second is the classic trap: you buy at “cheap” and sit for weeks while the 40% stays on paper. Liquidity and the risk metrics beside the margin are what decide.

What Mercator takes off your plate

The tool does part of this work for you. In the “What to buy” scoring, liquidity, volatility and spread persistence are already baked into the score and the position’s “confidence”, and trades on a dead book are filtered out by gates. In Arbitrage the destination hub is cut by daily volume, so you don’t haul goods to where no one will buy them. On the raw Market the filters are yours, but the logic is the same: liquidity and risk first, margin second.